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Mark Brownc26964e2009-10-01 15:41:06 +01001/*
2 * Backup battery driver for Wolfson Microelectronics wm831x PMICs
3 *
4 * Copyright 2009 Wolfson Microelectronics PLC.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/module.h>
12#include <linux/err.h>
13#include <linux/platform_device.h>
14#include <linux/power_supply.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090015#include <linux/slab.h>
Mark Brownc26964e2009-10-01 15:41:06 +010016
17#include <linux/mfd/wm831x/core.h>
18#include <linux/mfd/wm831x/auxadc.h>
19#include <linux/mfd/wm831x/pmu.h>
20#include <linux/mfd/wm831x/pdata.h>
21
22struct wm831x_backup {
23 struct wm831x *wm831x;
24 struct power_supply backup;
25};
26
27static int wm831x_backup_read_voltage(struct wm831x *wm831x,
28 enum wm831x_auxadc src,
29 union power_supply_propval *val)
30{
31 int ret;
32
33 ret = wm831x_auxadc_read_uv(wm831x, src);
34 if (ret >= 0)
35 val->intval = ret;
36
37 return ret;
38}
39
40/*********************************************************************
41 * Backup supply properties
42 *********************************************************************/
43
44static void wm831x_config_backup(struct wm831x *wm831x)
45{
46 struct wm831x_pdata *wm831x_pdata = wm831x->dev->platform_data;
47 struct wm831x_backup_pdata *pdata;
48 int ret, reg;
49
50 if (!wm831x_pdata || !wm831x_pdata->backup) {
51 dev_warn(wm831x->dev,
52 "No backup battery charger configuration\n");
53 return;
54 }
55
56 pdata = wm831x_pdata->backup;
57
58 reg = 0;
59
60 if (pdata->charger_enable)
61 reg |= WM831X_BKUP_CHG_ENA | WM831X_BKUP_BATT_DET_ENA;
62 if (pdata->no_constant_voltage)
63 reg |= WM831X_BKUP_CHG_MODE;
64
65 switch (pdata->vlim) {
66 case 2500:
67 break;
68 case 3100:
69 reg |= WM831X_BKUP_CHG_VLIM;
70 break;
71 default:
72 dev_err(wm831x->dev, "Invalid backup voltage limit %dmV\n",
73 pdata->vlim);
74 }
75
76 switch (pdata->ilim) {
77 case 100:
78 break;
79 case 200:
80 reg |= 1;
81 break;
82 case 300:
83 reg |= 2;
84 break;
85 case 400:
86 reg |= 3;
87 break;
88 default:
89 dev_err(wm831x->dev, "Invalid backup current limit %duA\n",
90 pdata->ilim);
91 }
92
93 ret = wm831x_reg_unlock(wm831x);
94 if (ret != 0) {
95 dev_err(wm831x->dev, "Failed to unlock registers: %d\n", ret);
96 return;
97 }
98
99 ret = wm831x_set_bits(wm831x, WM831X_BACKUP_CHARGER_CONTROL,
100 WM831X_BKUP_CHG_ENA_MASK |
101 WM831X_BKUP_CHG_MODE_MASK |
102 WM831X_BKUP_BATT_DET_ENA_MASK |
103 WM831X_BKUP_CHG_VLIM_MASK |
104 WM831X_BKUP_CHG_ILIM_MASK,
105 reg);
106 if (ret != 0)
107 dev_err(wm831x->dev,
108 "Failed to set backup charger config: %d\n", ret);
109
110 wm831x_reg_lock(wm831x);
111}
112
113static int wm831x_backup_get_prop(struct power_supply *psy,
114 enum power_supply_property psp,
115 union power_supply_propval *val)
116{
117 struct wm831x_backup *devdata = dev_get_drvdata(psy->dev->parent);
118 struct wm831x *wm831x = devdata->wm831x;
119 int ret = 0;
120
121 ret = wm831x_reg_read(wm831x, WM831X_BACKUP_CHARGER_CONTROL);
122 if (ret < 0)
123 return ret;
124
125 switch (psp) {
126 case POWER_SUPPLY_PROP_STATUS:
127 if (ret & WM831X_BKUP_CHG_STS)
128 val->intval = POWER_SUPPLY_STATUS_CHARGING;
129 else
130 val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
131 break;
132
133 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
134 ret = wm831x_backup_read_voltage(wm831x, WM831X_AUX_BKUP_BATT,
135 val);
136 break;
137
138 case POWER_SUPPLY_PROP_PRESENT:
139 if (ret & WM831X_BKUP_CHG_STS)
140 val->intval = 1;
141 else
142 val->intval = 0;
143 break;
144
145 default:
146 ret = -EINVAL;
147 break;
148 }
149
150 return ret;
151}
152
153static enum power_supply_property wm831x_backup_props[] = {
154 POWER_SUPPLY_PROP_STATUS,
155 POWER_SUPPLY_PROP_VOLTAGE_NOW,
156 POWER_SUPPLY_PROP_PRESENT,
157};
158
159/*********************************************************************
160 * Initialisation
161 *********************************************************************/
162
163static __devinit int wm831x_backup_probe(struct platform_device *pdev)
164{
165 struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
166 struct wm831x_backup *devdata;
167 struct power_supply *backup;
Alan Cox0e19dbb2009-11-17 15:44:54 +0000168 int ret;
Mark Brownc26964e2009-10-01 15:41:06 +0100169
170 devdata = kzalloc(sizeof(struct wm831x_backup), GFP_KERNEL);
171 if (devdata == NULL)
172 return -ENOMEM;
173
174 devdata->wm831x = wm831x;
175 platform_set_drvdata(pdev, devdata);
176
177 backup = &devdata->backup;
178
179 /* We ignore configuration failures since we can still read
180 * back the status without enabling the charger (which may
181 * already be enabled anyway).
182 */
183 wm831x_config_backup(wm831x);
184
185 backup->name = "wm831x-backup";
186 backup->type = POWER_SUPPLY_TYPE_BATTERY;
187 backup->properties = wm831x_backup_props;
188 backup->num_properties = ARRAY_SIZE(wm831x_backup_props);
189 backup->get_property = wm831x_backup_get_prop;
190 ret = power_supply_register(&pdev->dev, backup);
191 if (ret)
192 goto err_kmalloc;
193
194 return ret;
195
196err_kmalloc:
197 kfree(devdata);
198 return ret;
199}
200
201static __devexit int wm831x_backup_remove(struct platform_device *pdev)
202{
203 struct wm831x_backup *devdata = platform_get_drvdata(pdev);
204
205 power_supply_unregister(&devdata->backup);
206 kfree(devdata);
207
208 return 0;
209}
210
211static struct platform_driver wm831x_backup_driver = {
212 .probe = wm831x_backup_probe,
213 .remove = __devexit_p(wm831x_backup_remove),
214 .driver = {
215 .name = "wm831x-backup",
216 },
217};
218
219static int __init wm831x_backup_init(void)
220{
221 return platform_driver_register(&wm831x_backup_driver);
222}
223module_init(wm831x_backup_init);
224
225static void __exit wm831x_backup_exit(void)
226{
227 platform_driver_unregister(&wm831x_backup_driver);
228}
229module_exit(wm831x_backup_exit);
230
231MODULE_DESCRIPTION("Backup battery charger driver for WM831x PMICs");
232MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
233MODULE_LICENSE("GPL");
234MODULE_ALIAS("platform:wm831x-backup");